upssched.exe and timer configuration on Windows NUT server RELEASE-2.8.5-1-fixNSS

[alexdruqn-cpu]

Problem with upssched in the Windows NUT build 2.8.5 - NUT-for-Windows-x86_64-RELEASE-2.8.5-1-fixNSS
In my scenario, I only need to poll a remote UPS and, on some Windows clients, decide when to shut down not based on FSD, but earlier than that. I chose to use upssched and its timers.
Upsmon starts upssched.exe on configured events, but the process cannot create PIPEFN and LOCKFN. Without these parameters, upssched.exe does not start at all. I tried different options, but in every case, at the very first NOTIFYFLAG state change, multiple instances of upssched.exe are launched — more than 10–20 or so — and they start the same timers in parallel and run the same file logging operations. At the same time, no working flags are created. For testing, I ran upsmon in the console; at the first state change, the console showed a message saying it was unable to establish communication with already running instances, along with many duplicated messages about launching my script from CMDSCRIPT.

c:\NUT\sbin>upsmon.exe
Network UPS Tools upsmon 2.8.5 release using a dynamic libnutprivate*
UPS: [testups@192.168.1.1](mailto:testups@192.168.1.1) (secondary) (power value 1)
Using power down flag file C:\NUT\killpower
Init SSL without certificate database
read confirmation got []
read confirmation got []
read confirmation got []
read confirmation got []
read confirmation got []
Unable to connect to daemon and unable to start daemon

messages from my log file:

[2026-07-13 12:05:04.070] PID=21392 EVENT=online_returned Entered handler
[2026-07-13 12:05:04.086] PID=21392 EVENT=online_returned Power returned, no shutdown marker present
[2026-07-13 12:05:04.094] PID=12528 EVENT=online_returned Entered handler
[2026-07-13 12:05:04.110] PID=12528 EVENT=online_returned Power returned, no shutdown marker present
[2026-07-13 12:05:04.118] PID=19696 EVENT=online_returned Entered handler
[2026-07-13 12:05:04.134] PID=19696 EVENT=online_returned Power returned, no shutdown marker present
[2026-07-13 12:05:04.140] PID=5900 EVENT=online_returned Entered handler
[2026-07-13 12:05:04.156] PID=5900 EVENT=online_returned Power returned, no shutdown marker present
[2026-07-13 12:05:04.166] PID=23924 EVENT=online_returned Entered handler
[2026-07-13 12:05:04.182] PID=23924 EVENT=online_returned Power returned, no shutdown marker present
[2026-07-13 12:05:04.254] PID=27780 EVENT=online_returned Entered handler
[2026-07-13 12:05:04.268] PID=27780 EVENT=online_returned Power returned, no shutdown marker present
[2026-07-13 12:05:04.320] PID=17404 EVENT=online_returned Entered handler
....
[2026-07-13 12:08:04.990] PID=20552 EVENT=online_returned Entered handler
[2026-07-13 12:08:05.006] PID=20552 EVENT=online_returned Power returned, no shutdown marker present
[2026-07-13 12:08:05.006] PID=19216 EVENT=online_returned Entered handler
[2026-07-13 12:08:05.037] PID=19216 EVENT=online_returned Power returned, no shutdown marker present
[2026-07-13 12:08:05.053] PID=3096 EVENT=online_returned Entered handler
[2026-07-13 12:08:05.085] PID=3096 EVENT=online_returned Power returned, no shutdown marker present
[2026-07-13 12:08:05.085] PID=7720 EVENT=online_returned Entered handler
[2026-07-13 12:08:05.101] PID=7720 EVENT=online_returned Power returned, no shutdown marker present

#upssched.conf
CMDSCRIPT "C:\NUT\cmd\upssched-cmd.cmd"
#PIPEFN "C:\\NUT\\upssched.pipe"
#LOCKFN "C:\\NUT\\upssched.lock"
#PIPEFN "C:\NUT\upssched.pipe"
#LOCKFN "C:\NUT\upssched.lock"
#PIPEFN "C:/NUT/upssched.pipe"
#LOCKFN "C:/NUT/upssched.lock"
#PIPEFN "/NUT/upssched.pipe"
#LOCKFN "/NUT/upssched.lock"
PIPEFN "\\.\pipe\upssched"
LOCKFN "C:\NUT\upssched.lock"
AT ONBATT * START-TIMER onbatt_shutdown 120
AT ONLINE * CANCEL-TIMER onbatt_shutdown online_returned
AT LOWBATT * EXECUTE lowbatt_shutdown

#upsmon.conf
MONITOR [testups@192.168.1.1](mailto:testups@192.168.1.1) 1 user user secondary
MINSUPPLIES 1
SHUTDOWNCMD "C:\Windows\System32\shutdown.exe /s /t 0 /f"
POLLFREQ 15
POLLFREQALERT 5
HOSTSYNC 15
DEADTIME 15
FINALDELAY 5
POWERDOWNFLAG "C:\NUT\killpower"
NOTIFYCMD "C:\NUT\sbin\upssched.exe"
NOTIFYFLAG ONLINE EXEC
NOTIFYFLAG ONBATT EXEC

[jimklimov]

One thing that pops out is that per NUT docs, backslashes as used in Windows paths must be escaped (as the backslash alone is an escape character for whichever one follows next). Can you show how it went with all the backslashes doubled in config files (I see lines like that commented away), e.g.

PIPEFN "\\\\.\\pipe\\upssched"
LOCKFN "C:\\NUT\\upssched.lock"

Your post does show upsmon logging Using power down flag file C:\NUT\killpower so maybe it did interpret the slashes correctly in some code paths (which would be more puzzling than relieving I guess, comparing to docs), or that screenshot came from different experiments than the config files posted in text.

Also, try setting NUT_DEBUG_LEVEL=6 before starting upsmon to have it log more verbosely and maybe showing what it tried to do and failed.

There was some issue posted after 2.8.5 release about lack of permissions to create pipes in some cases - maybe this situation is an instance of that. I think the proposed fix was merged a couple of weeks ago, so regular master-branch builds from Appveyor CI should let it be tested, assuming it was applied to all pipe-creating programs :)

UPDATE: Probably I meant PR #3479 - and it only dealt with driver sockets/pipes.

[alexdruqn-cpu]

it is copy/paste/word/ai issues with backslashes. In config files all backslahes are escaped. Except for the experiments that are in the comments.
I vibecoded my own NOTIFYCMD handler in PowerShell and I was satisfied with the result without using upssched timers, but a little later I'm ready to post more complete logs with the maximum debugging level using the built-in upssched solution.

#upssched.conf
#CMDSCRIPT "C:\\NUT\\cmd\\upssched-cmd.cmd"
CMDSCRIPT "C:\\Windows\\System32\\WindowsPowerShell\\v1.0\\powershell.exe -NoProfile -ExecutionPolicy Bypass -File C:\\NUT\\cmd\\upssched-cmd.ps1"
#PIPEFN "C:\\NUT\\upssched.pipe"
#LOCKFN "C:\\NUT\\upssched.lock"
#PIPEFN "C:/NUT/upssched.pipe"
#LOCKFN "C:/NUT/upssched.lock"
#PIPEFN "/NUT/upssched.pipe"
#LOCKFN "/NUT/upssched.lock"

PIPEFN "\\\\.\\pipe\\upssched"
LOCKFN "C:\\NUT\\upssched.lock"
AT ONBATT * START-TIMER onbatt_shutdown 120
AT ONLINE * CANCEL-TIMER onbatt_shutdown online_returned
AT LOWBATT * EXECUTE lowbatt_shutdown

MONITOR testups@192.168.1.1 1 user user secondary
MINSUPPLIES 1
SHUTDOWNCMD "C:\\Windows\\System32\\shutdown.exe /s /t 0 /f"
POLLFREQ 15
POLLFREQALERT 5
HOSTSYNC 15
DEADTIME 15
FINALDELAY 5
POWERDOWNFLAG "C:\\NUT\\killpower"
NOTIFYCMD "C:\\NUT\\sbin\\upssched.exe -D"
NOTIFYFLAG ONLINE EXEC
NOTIFYFLAG ONBATT EXEC

[jimklimov]

Fair enough, although getting to the root of this issue and fixing it would be great.

For future-proofness, also note that in eventual NUT v2.8.6, and master-branch builds after the merge of PR #3499, NOTIFYCMD and CMDSCRIPT must contain only paths; if more args are needed - point to a script(let) which contains them and safely evaluates further arguments that may be passed by upsmon/upssched according to their CLI API definitions.

[alexdruqn-cpu]

I've done tests with an increased diagnostic level. The configuration files have not changed, I have only added the NOTIFYMSG descriptions to reduce the number of diagnostic entries. I left the output of powershell errors in the console caused by attempts to write to the same log file by different processes.

Unable to connect to daemon and unable to start daemon on 532 line console.log

Console_5.8.5_1.txt

# upssched-cmd.ps1
param(
    [string]$EventName
)

$LogDir = 'C:\NUT\log'
$LogFile = Join-Path $LogDir 'upssched_test_2.log'

if (-not (Test-Path $LogDir)) {
    New-Item -ItemType Directory -Path $LogDir -Force | Out-Null
}

function Write-Log {
    param([string]$Message)
	try {
		$ts = Get-Date -Format 'yyyy-MM-dd HH:mm:ss'
	    Add-Content -Path $LogFile -Value "[$ts] $Message"
    }
       catch {
        }
}

Write-Log "UPSCMD=$EventName"

switch ($EventName) {
    'onbatt_shutdown' {
        Write-Log 'Triggering Windows shutdown'
        Start-Process -FilePath 'C:\Windows\System32\shutdown.exe' -ArgumentList '/s /t 0 /f' -WindowStyle Hidden
        break
    }

    'lowbatt_shutdown' {
        Write-Log 'Triggering Windows shutdown due to LOWBATT'
        Start-Process -FilePath 'C:\Windows\System32\shutdown.exe' -ArgumentList '/s /t 0 /f' -WindowStyle Hidden
        break
    }

    'online_returned' {
        Write-Log 'Power returned, timer cancelled'
        break
    }

    default {
        Write-Log "Unknown event: $EventName"
        break
    }
}